Changing an object menu on the activity feed

I have created a new object and when an instance of this object is create the river is updated and the action is displayed on the activity feed whihc is great.  

Unfortunely on river view for the object,  I want to remove the ability for user to comment on this action, is any body able to provide me with guidance on how to achieve this.

thanks

Beginning Developers

Beginning Developers

This space is for newcomers, who wish to build a new plugin or to customize an existing one to their liking